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Cat-3560 and auto qos.

I need to have a Cat-3560 honor the DSCP values of packets traveling through it. On the switchports I have:

auto qos voip trust

mls qos trust dscp

Two of the ports on the 3560 are routed ports so do I need to put 'auto qos...' and the 'mls qos...' on those ports too for the dscp values to be honored going through those ports?


Re: Cat-3560 and auto qos.

Hello there,


Auto-QoS Configuration Guidelines

Before configuring auto-QoS, you should be aware of this information:

•In releases earlier than Cisco IOS Release 12.2(20)SE, auto-QoS configures VoIP only on switch ports with Cisco IP Phones.

•In Cisco IOS Release 12.2(20)SE or later, auto-QoS configures the switch for VoIP with Cisco IP Phones on nonrouted and routed ports. Auto-QoS also configures the switch for VoIP with devices running the Cisco SoftPhone application.



if it does, please rate this post.


Re: Cat-3560 and auto qos.

You can either trust or not enable mls qos at all. If MLS QoS is not enable the switch will not touch the DSCP, so there is really nothing to do if all you want the switch to do is not alter the incoming DSCP untouched.

Please rate helpful posts.

New Member

Re: Cat-3560 and auto qos.

Yes - I don't want the switch to alter the DSCP values - as the PBX and IP phones will set them the way I want. But I do want to supply some form of QOS for the VoIP packets traversing the switch - just in case the uplinks get congested the voice packets will get better queueing.

So I think I'll go ahead and apply both commands to the routed ports. - Thanks

Re: Cat-3560 and auto qos.

You're welcome,

Just remember to rate helpful posts.


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